Receiver mod pics

The receiver mod is probably the most daunting of the changes you will need to make to your rifle. Here are a few pics to help make it easier to understand what to do. Essentially you are creating enough space for the XCR magazine to fit into the receiver.

Top pic shows an unmodified SKS receiver from below. The "bullet ramps" are clearly visible.

Bottom pic shows a modified receiver. Front and sides of ramps are milled back. I would give dimensions but it seems to me every one of these fittings should be treated as a unique custom project. The main idea here is to allow an XCR mag to just fit into the space after all mods are complete.

Perodically check fitment as you go.

Pic illustrates that you can get a rough idea how much to cut without having to assemble the whole unit every time to check.

Bolt Hold Open (BHO) modification

Marcus (the original inventor of the G9) suggests shortening the BHO by 0.2". I imagine he means that you should remove this amount from the bottom of the "nose" of the BHO, but I found that we had to remove other material as well. Bear in mind that Marcus is working in the USA and is able to modify his magazines as well, so that may be the source of the difference here.

Here is a BHO in original condition. There can be variations in shape so again, we must treat each installation as a custom job. The main idea here is to remove just enough material to allow the BHO to function.

Here I marked in red the areas we ended up milling away. I would start with the underside of the nose and proceed from there to remove only as much as necessary from your BHO. Try to see what parts get in the way of the proper function of the BHO, and only when you are quite certain, cut away metal. I would treat any measurements given with caution, and as rough guideline only.

A BHO in the rifle. Mods have been completed as can be seen by the fresh cut metal. I see now that I forgot to mark the front tip of the nose as slightly cut back. We found out sometime later that this needed to be done as the BHO was not operating correctly. Best to leave this mod until you can observe a problem with functioning and then cut only as much as necessary.

The pin that needs pressing out to remove the BHO is visible .... some seem to be very difficult to extract. Beware of losing the spring under the BHO, as once retaining pin is removed the unit can pop out with considerable force.

Re-installing the BHO: water pump pliers work very well for putting even pressure on pins that need replacing.

Bolt modification

The bolt modification is necessary for the "Canadian installation" of the G9.

The sides must be shaved to allow the bolt to pass cleanly between the feed lips of the XCR magazine. We also found that the bolt would bind and fail to go fully into battery unless a small groove was cut in the bottom of the bolt to prevent the front edge of the mag from exerting upward pressure on the bolt.

Any modifications to the bolt must be considered with some care. If you search around you will see a great many versions of this modification. We chose to alter the bolt as minimally as possible, and to above all avoid damaging the front face of the bolt. The bottom groove we cut lines up with the front edge of the magazine and is set back a comfortable distance from the bolt face.

Top pic shows the view of the bottom of the modified bolt. The sides have been shaved and the groove we cut is visible near the front of the bolt.

Middle pic shows a side view of the same thing.

Bottom pic shows the result we are aiming to acheive: the bolt passes freely between the XCR magazine lips. Note notch in bolt bottom just above the front of the magazine. This allows the bolt to go into full battery as there is now enough clearance with front edge of the magazine.

Finishing touches

A comparison of an unaltered rifle and a modified receiver and a modified stock.

We added a set screw to our version of the G9.

This is inserted after the installation is complete and the rifle has been "function tested" with snap caps or other inert ammunition. The effect is to secure the assembly and allow for fine tuning of the installation. Set screw should be installed firmly but beware of over tightening as a lot of pressure can be put on a part with a screw. Light locktite may be used if desired.

What we hope to end up with: rifle and G9 assembled as a working unit.